Remove additional messages from 404 JSON response in Zend Framework 2

Question

I'm creating a RESTful API in ZF2 returning JSON responses for each route. For one of the routes, I need to return a 404 response, but return $this->notFoundAction(); is not acceptable as it returns a view rather than JSON. I'm therefore doing the following:

$response = $this->getResponse();
$response->setStatusCode(404);
return new JsonModel(array(
    'error_message' => "Client $clientRef doesn't exist"
));

Testing this, I get the response fine with a 404 status code, and my error message is displayed. However, there are other Zend-generated messages included as part of the response:

{
    "error_message": "Client test-client doesn't exist",
    "message": "Page not found.",
    "reason": "error-controller-cannot-dispatch",
    "display_exceptions": true,
    "controller": "Timesheet\\Controller\\TimesheetRest",
    "controller_class": null
}

If I change display_not_found_reason and display_exceptions both to false in the config, then it will remove some of the additional details, but message still remains:

{
    "error_message": "Client test-client doesn't exist",
    "message": "Page not found."
}

How do I remove all the extra details from the response body?

^{Note that I only get these messages when returning a 404 status. When returning 400, 403, or 409, it is only my error message that is returned, without any additional messages.}

Not sure if it's relevant, but the config file for the module in question is as follows (note I have 2 controllers, one for the front-end, and one for the API):

<?php
return array(
    'controllers' => array(
        'invokables' => array(
            'Timesheet\Controller\Timesheet' => 'Timesheet\Controller\TimesheetController',
            'Timesheet\Controller\TimesheetRest' => 'Timesheet\Controller\TimesheetRestController'
        )
    ),
    'router' => array(
        'routes' => array(
            'timesheet' => array(
                'type' => 'Segment',
                'options' => array(
                    // Change this to something specific to your module
                    'route' => '/timesheet[/:action][/:id]',
                    'defaults' => array(
                        // Change this value to reflect the namespace in which
                        // the controllers for your module are found
                        '__NAMESPACE__' => 'Timesheet\Controller',
                        'controller' => 'Timesheet',
                        'action' => 'index'
                    ),
                    'constraints' => array(
                        'action' => 'index|pending|review|save|submit|unauthorised',
                        'id' => '[1-9][0-9]*'
                    )
                )
            ),
            'timesheet-rest' => array(
                'type' => 'Segment',
                'options' => array(
                    // Change this to something specific to your module
                    'route' => '/api/timesheet[/:id]',
                    'defaults' => array(
                        // Change this value to reflect the namespace in which
                        // the controllers for your module are found
                        '__NAMESPACE__' => 'Timesheet\Controller',
                        'controller' => 'TimesheetRest',
                    ),
                    'constraints' => array(
                        'id' => '[1-9][0-9]*'
                    )
                )
            ),
        )
    ),
    'view_manager' => array(
        'strategies' => array(
            'ViewJsonStrategy'
        ),
        'template_path_stack' => array(
            'Timesheet' => __DIR__ . '/../view'
        )
    )
);

Answer 1

Show blank message

After looking through Zend/Mvc/View/Http/RouteNotFoundStrategy there is a function prepareNotFoundViewModel which is what adds message to the response. However, this only happens when message isn't already defined. Changing my code to this:

$response = $this->getResponse();
$response->setStatusCode(404);
return new JsonModel(array(
    'message' => '',
    'error_message' => "Client $clientRef doesn't exist"
));

would then give me a response body of:

{
    "message": "",
    "error_message": "Client test-client doesn't exist"
}

which at least removes confusion between the two messages.

Remove message

However, changing the code to return the response directly, instead of using a JsonModel, stops message from being injected at all. The following code:

$response = $this->getResponse();
$response->setStatusCode(404);
$response->setContent(json_encode(array(
    'error_message' => "Client $clientRef doesn't exist"
)));
return $response;

gives this as a response:

{
    "error_message":"Client test-client doesn't exist"
}